The pipe is a little "penny side" heavy due to the mass off center. You can see that there is quite a bit of rotation on the penny that will allow contact to be maintained. Since the hole in the penny where it pivots is off center, it is in fact an eccentric cam. This allows a fair amount of height adjustment by rotating the penny. The next one I will drill the positive and switched brass screw hole to allow the proper angle for reading a book, newspaper or magazine.